Cloning and characterization of a water deficit stress responsive transcription factor gene from Oryza sativa L.

Understanding the biochemical and molecular basis of drought mechanism in rice is important as drought is one of the major causes affecting rice crop adversely. A 1017 bp gene sequence encoding AP2/ERF family TF was isolated from Oryza sativa sp. Indica cv N22 encoding a protein of 338 amino acid residues, with a molecular weight of 36.58 kDa, and no intron in the ORF. The gene was named as AP2/ERF-N22(2) different from the drought responsive gene AP2/ERF-N22 that we reported earlier. AP2/ERF-N22(2) has entirely different characteristics from that of AP2/ERF-N22. It has a single AP2 domain of 55 amino acid residues and a cluster of acidic amino acid residues at the C-terminal region, which could function as a trans-activation domain. Presence of NLS indicates that it is a nuclear localized transcription factor encoding gene. It falls in group VI L, sharing characteristic similarities. Arabidopsis members of group VI L have been shown to be involved in response to cytokinin under drought stress.